Hi, so I have this mould that will be used just one time and theb scrapped.
It is made with epoxy gelcoat and a few layers of 200gsm cloth laminated with epoxy.
I want to infuse the part and I think the mould is too flexible for the job.
What do you suggest as the cheapest way to stiffen it?
I was thinking about breather cloth impregnated with cheap polyester resin but maybe you have better and cheaper ideas?

Thanks for any advice!

As oakmont says, eps or some foam or even wood strips used as stiffening ribs.  Couple of layers of glass over and it should help considerably. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant